no one could __ failed to notice the fact that ///is a grave problem,这边是用has还是have

分类: 作业答案 • 2022-01-07 12:00:14

问题描述：

no one could __ failed to notice the fact that ///is a grave problem,这边是用has还是have
为什么呢

答

have
could have +过去分词 - 虚拟语气的固定形式